In the electronics industry, the tendency has been to reduce the size of electronic devices such as camcorders and portable telephones while increasing performance and speed. Integrated circuit packages for complex systems typically are comprised of multiple interconnected integrated circuit chips. The integrated circuit chips usually are made from a semiconductor material such as silicon or gallium arsenide. The integrated circuit chips may be mounted in packages that are then mounted on printed wiring boards.
Typically, the packages on which these integrated semiconductor chips are mounted include a substrate or other chip-mounting device. Semiconductor chips may be attached to the substrate using adhesive or any other techniques for attaching such chips to a substrate which are commonly known to those skilled in the art. The power, ground and/or signal sites on the chip may then be electrically connected to individual leads on the substrate through techniques such as wire bonding.
An interposer is an electrical interface routing between one socket or connection to another. It is an intermediate layer often used for interconnection routing or as a ground/power plane. When multiple chips are mounted within the same semiconductor package, routing problems may arise due to the different routing design of each individual chip. To solve this problem, an interposer is often used. Sometimes the terms ‘substrate’ and ‘interposer’ are used to refer to the same thing.
An internal stacking module (ISM) is typically a semiconductor integrated package that has certain designed-in functionalities. In modern semiconductor manufacturing, an ISM is typically used as an off-the-shelf component for a more complex semiconductor integrated package. Such a scheme makes integrating semiconductor chips more efficient and more cost-effective. A semiconductor package that has an ISM as a component is typically called a Package-in-Package (PiP) package.
Conventionally, one or more semiconductor dies are manufactured and are mounted on a main substrate. Afterwards, an ISM is attached to the mounted semiconductor die(s) using a spacer layer and an adhesive layer. Then, the different parts of the assembly are encapsulated in a mold compound. A singulation process is utilized to realize individually separated semiconductor packages.
A problem with the conventional PiP package is that warpage of the embedded ISM often occurs. This is because the spacer layer and the adhesive layer that connect the ISM to the mounted semiconductor die(s) are often positioned at the center of the ISM so that the stress exerted upon the ISM is not uniform across the ISM. Such a warpage has increased the rate of failure of the ISM and consequently the rate of failure of the PiP package and in turn increased the cost of the PiP package.
Another problem with the conventional PiP package is that tilting of the embedded ISM often occurs. Tilting occurs when the ISM rotates around a pivot point, which is the contact point between the ISM and the mounted semiconductor die(s). This is also due to the fact that the spacer layer and the adhesive layer that connect the ISM to the mounted semiconductor die(s) are often positioned at the center of the ISM and are often of small contact area so that the adhesion of the ISM to the mounted semiconductor die(s) is inadequate. Such a tilting has increased the rate of failure of the ISM and consequently the rate of failure of the PiP package and in turn increased the cost of the PiP package.
Thus, a need still remains for reducing the warpage and tilting problems of the PiP packages and also for reducing the cost of such PiP packages. In view of the ever-increasing commercial competitive pressures, along with growing consumer expectations and the diminishing opportunities for meaningful product differentiation in the marketplace, it is critical that answers be found for these problems. Additionally, the need to reduce costs, improve efficiencies and performance, and meet competitive pressures, adds an even greater urgency to the critical necessity for finding answers to these problems.
Solutions to these problems have been long sought but prior developments have not taught or suggested any solutions and, thus, solutions to these problems have long eluded those skilled in the art.